Yesterday a 23-year-old South Korean student was identified as the gunman who slaughtered 32 people at Virginia Tech on Monday, in the worst campus shooting spree among a list of similar horrors that have become one of the defining features of the United States to the outside world. The US is not the only country in which random acts of gun violence have erupted in seemingly everyday circumstances to destroy lives, families and communities. But the US is one of the few countries that seems collectively unwilling and politically incapable of doing anything serious to stop such things happening again.

Whereas other countries - Britain after the 1996 Dunblane school massacre, Australia following the shootings in Tasmania the same year - have responded to such incidents by attempting to restrict access to guns, the US has not. Yesterday, as too often before, Americans instinctively drew together to mourn the dead and support the living. The president and the state governor both hurried to Blacksburg to lead and share the community's grief. Their expressions of solidarity are the right immediate response. But, if history is any guide, that is as far as it will go. Once again, the rest of the world will look on in amazement as America proves itself unable to defend its ordinary citizens from its armed maniacs.

The first duty of any government is to protect its people. But in this respect the United States government cannot. Opinion polls show that most Americans want the nation's gun laws to be stricter; often such polls reveal majorities of roughly two to one. Yet US leaders are held hostage by the power of the gun lobby and the electoral system. Most Republicans oppose gun controls of any kind anyway. But the formidable National Rifle Association is too potent a foe for any party to take on. Over the years the Democrats have made their choice. They can either campaign for gun control or win power, but not both; they prefer power.

There is a long-standing dispute about whether the bearing of arms was integral to the United States from the start or whether, had it not been for a later-developing gun-owning culture, the US would have the more balanced approach that exists across the border in Canada. One day, perhaps, the supreme court may decide. In the meantime, not even this week's events will change the political reality. Modest attempts to tighten gun control laws in the 1990s - by restricting access to certain heavy weapons, for example, or by strengthening background checks on buyers - were bitterly resisted at every level, especially in states such as Virginia. That enduring civic failure is one of the reasons why Virginia families are weeping over the graves of their dead children this week.